Marine Biotechnology
 

Environmental Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 13 No. 1, Issue of January 15, 2010
© 2010 by Pontificia Universidad Católica de Valparaíso -- Chile Received March 15, 2009 / Accepted July 31, 2009
DOI: 10.2225/vol13-issue1-fulltext-2
RESEARCH ARTICLE

Inhibition of shrimp pathogenic vibrios by extracellular compounds from a proteolytic bacterium Pseudomonas sp. W3 

Pattamarat Rattanachuay
Department of Microbiology
Faculty of Science
Prince of Songkla University
Hat Yai, 90112, Thailand

Duangporn Kantachote*
Department of Microbiology
Faculty of Science
Prince of Songkla University
Hat Yai, 90112, Thailand
E-mail: duangporn.k@psu.ac.th

Manee Tantirungkij
Central Laboratory and Greenhouse Complex
Kasetsart University, Kamphaeng Sean Campus
Nakhon Pathom 73140, Thailand

Teruhiko Nitoda
The Graduate School of Natural Science and Technology
Okayama University
Okayama 7008530, Japan

Hiroshi Kanzaki
The Graduate School of Natural Science and Technology
Okayama University
Okayama 7008530, Japan

Website: http://www.psu.ac.th

*Corresponding author

Financial support: This work was supported by a Graduate School Songklanakarin Scholarship, 2007-2009, Graduate School and Faculty of Science, Prince of Songkla University, Thailand.

Keywords: bacteriolytic enzymes, bioactive compounds, Pseudomonas sp. W3, shrimp pathogenic bacteria, Vibrio spp.

Abbreviations:

FGM: Frazier gelatin medium
rpm: revolution per minute
SEM: scanning electron microscope
TEM: transmission electron microscope
TSA: tryptic soy agar
TSB: tryptic soy broth

Abstract   Full Text

Pseudomonas sp. W3, a bacterium known to produce an extracellular alkaline protease, secreted secondary metabolites that inhibited pathogenic bacteria responsible for shrimp luminous vibriosis disease. Antivibrio compounds in the culture supernatant or culture filtrates (0.45 µm and 0.22 µm) of the isolate W3 were tested using an agar well diffusion method on a number of pathogenic vibrios. Vibrio harveyi PSU 2015 a pathogenic isolate was the most sensitive strain. The effectiveness of preparations from the isolate W3 against V. harveyi PSU 2015, and V. cholerae PSSCMI 0062 was in the order of culture supernatant > 0.45 µm culture filtrate > 0.22 µm culture filtrate. These extracellular antivibrio compounds also lysed both dead and living cells of V. harveyi PSU 2015. Results of the partial characterization tests indicated that there was some particulate antivibrio compound that was destroyed by treatment with enzymes particularly α-chymotrypsin, autoclaving at 121ºC for 15 min and was mostly removed by filtration through a 0.22 µm filter. Most of the inhibitory compounds were of small molecular weight able to pass through a 0.22 µm filter and were resistant to treatment with various enzymes, pH values between 4-8 and temperatures up to 121ºC for 30 min. The optimum pH for the antivibrio activity in the 0.45 µm culture filtrate was between pH 6-7.

Supported by UNESCO / MIRCEN network